In recent years there has been a significant increase in the development of procedures that combine architectural control with flexibility in the incorporation of functional groups due to the increasing demand for functionalized soft materials. Well-defined three-dimensional structures such as microgels, star polymers, micelles, and dendrimers have been explored because they are considered to be building blocks for a variety of nanotechnology applications that take advantage of the high number of functional groups. In particular, star polymers, which are composed of multiple polymer chains emanating from a central core, have advantages due to their compact structure and synthetic ease of preparation. Likewise, analytical technologies have developed that allow in vivo imaging of cells and tissue structures. For example, fluorescence detection and magnetic resonance imaging (MRI) allow for imaging of microstructures within subjects with a high degree of resolution.
Conventional techniques, however, fail to provide water-soluble, well-defined, three-dimensional nanostructures capable of cell membrane transport and imaging by more than one detection method. Further, conventional techniques fail to provide satisfactory contrast for imaging by MRI. There deficiencies and other deficiencies are remedied by the disclosed compositions and methods.